Yes, withe Edge on MORE Everything you get $20 off the lines access charge for plans 10GB and up. You still have to pay for the data access charge in addition to the line access charge.
What exactly is your question?
The $20 comes off the line fee not the data fee. Going from 6 GB to 10 is $20 so basically you $20 savings is basically going to get 4 more GB. If you're not interested in having more than 6GB you can leave it there and still get $10 a month off.
Anyway you bill would be
Line Fee $20( $40-$20 discount for Edge )
Edge Payment $27.08
Data Plan 10GB $100
So your total would be $147.08 plus taxes and fees. I am assuming you have a single line.